electrolytes

Abstract

To provide a novel Ta chloride-based electrolyte useful for sodium-ion batteries. [Solution] formula: NaTaCl6·xNaCl [In the equation, x is between 1 and 15 (inclusive).] An electrolyte represented by [a specific symbol / method].

Description

Technical Field

[0001] The present disclosure relates to an electrolyte, particularly a chloride-based electrolyte useful as a solid electrolyte for a sodium-ion battery.

Background Art

[0002] In Patent Document 1, it is disclosed that a sodium halide-based nanocomposite is useful as a battery material.

Prior Art Documents

Patent Documents

[0003] US2023 / 0411616A1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, there is no specific disclosure about Ta-based compounds, particularly Ta chlorides, and the ionic conductivity and the like of Ta-based compounds have not been studied. [[ID=3)4]]

[0005] An object of the present disclosure is to provide a novel Ta chloride-based electrolyte useful for a sodium-ion battery.

Means for Solving the Problems

[0006] The present disclosure includes the following aspects: [Item 1] [Formula: NaTaCl6·xNaCl [where x is 1 or more and 15 or less.] An electrolyte represented by the above formula. [Item ] The electrolyte according to Item 1, where x is 4 or more and 11 or less. [Item 3] In the above electrolyte, the amount of amorphous is 10% by volume or more, the amount of NaCl crystals is 10% by volume or more, The electrolyte according to item 1 or 2, wherein the amount of NaTaCl6 crystals is 60% by volume or less. [Section 4] In the aforementioned electrolyte, The amount of amorphous material is 30% by volume or more and 60% by volume or less. The amount of NaCl crystals is between 30% by volume and 70% by volume. An electrolyte according to any one of items 1 to 3, wherein the amount of NaTaCl6 crystals is 30% by volume or less. [Section 5] A solid electrolyte for all-solid-state sodium-ion batteries, as described in any one of items 1 to 4. [Section 6] A positive electrode containing the electrolyte described in any one of items 1 to 5. [Section 7] A negative electrode containing the electrolyte described in any one of items 1 to 5. [Section 8] An electrolyte layer containing the electrolyte described in any one of items 1 to 5. [Section 9] A battery comprising a battery component containing an electrolyte as described in any one of items 1 to 5. [Section 10] formula: NaTaCl6·xNaCl [In the equation, x is between 1 and 15 (inclusive).] A method for producing an electrolyte, represented by the following: A manufacturing method comprising a mechanochemical process for mixing and reacting raw materials. [Effects of the Invention]

[0007] The electrolyte in this disclosure has good sodium ion conductivity and is particularly useful as a solid electrolyte for sodium ion batteries. Furthermore, the electrolyte in this disclosure can be industrially advantageous because it can use inexpensive NaCl in a high proportion as a raw material. [Modes for carrying out the invention]

[0008] <Electrolytes> [Electrolyte properties, etc.] The electrolyte in this disclosure has good ionic conductivity and is useful as a solid electrolyte for sodium-ion batteries.

[0009] [Electrolyte composition, etc.] The electrolyte in this disclosure is given by formula: NaTaCl6·xNaCl [In the equation, x is between 1 and 15 (inclusive).] It can be expressed as follows.

[0010] x may be 1 or more, 3 or more, 5 or more, 7 or more, 9 or more, 11 or more, or 13 or more, and may also be 15 or less, 14 or less, 12 or less, 10 or less, 8 or less, or 6 or less, and in one embodiment it is 4 or more and 12 or less, particularly 5 or more and 10 or less. It is preferable from the viewpoint of good ionic conductivity that x be within the above range (for example, 4 or more and 11 or less, preferably 5 or more and 11 or less, more preferably 6 or more and 10 or less, particularly 7 to 9). Furthermore, the higher x is, the more inexpensive NaCl can be used as a raw material, which is industrially advantageous.

[0011] The electrolyte preferably contains amorphous material and NaCl crystals. The electrolyte may further contain NaTaCl6 crystals.

[0012] The amount of amorphous material may be 10% or more by volume, 20% or more by volume, 30% or more by volume, 40% or more by volume, 50% or more by volume, or 60% or more by volume, preferably 30% or more by volume, and may also be 90% or less by volume, 80% or less by volume, 70% or less by volume, 60% or less by volume, 50% or less by volume, 40% or less by volume, or 30% or less by volume, preferably 60% or less by volume, and in one embodiment, 30% or more by volume and 60% or less by volume. By setting it within the above range, good ionic conductivity can be achieved.

[0013] The amount of NaCl crystals may be 10% by volume or more, 20% by volume or more, 30% by volume or more, 40% by volume or more, 50% by volume or more, or 60% by volume or more, preferably 30% by volume or more, and may also be 90% by volume or less, 80% by volume or less, 70% by volume or less, 60% by volume or less, 50% by volume or less, 40% by volume or less, or 30% by volume or less, preferably 70% by volume or less, and in one embodiment, 30% by volume or more and 70% by volume or less. By setting the amount within the above range, good ionic conductivity can be achieved.

[0014] The amount of NaTaCl6 crystals may be 0 vol% or more, 5 vol% or more, 10 vol% or more, 15 vol% or more, 20 vol% or more, 30 vol% or more, or 40 vol% or more, and may also be 60 vol% or less, 50 vol% or less, 40 vol% or less, 30 vol% or less, 20 vol% or less, 10 vol% or less, 5 vol% or less, 3 vol% or less, or 1 vol% or less, preferably 30 vol% or less, and in one embodiment, 0 vol% or more and 30 vol% or less. By setting it within the above range, good ionic conductivity can be achieved.

[0015] The amount of amorphous material may be 15% by weight or more, 25% by weight or more, 35% by weight or more, 45% by weight or more, 55% by weight or more, or 65% by weight or more, preferably 35% by weight or more, and may also be 95% by weight or less, 85% by weight or less, 75% by weight or less, 65% by weight or less, 55% by weight or less, 45% by weight or less, or 35% by weight or less, preferably 65% ​​by weight or less, and in one embodiment it is 35% by weight or more and 65% by weight or less. By setting it within the above range, good ionic conductivity can be achieved.

[0016] The amount of NaCl crystals may be 5% by weight or more, 15% by weight or more, 25% by weight or more, 35% by weight or more, 45% by weight or more, or 55% by weight or more, preferably 25% by weight or more, and may also be 85% by weight or less, 75% by weight or less, 65% by weight or less, 55% by weight or less, 45% by weight or less, 35% by weight or less, or 25% by weight or less, preferably 65% ​​by weight or less, and in one embodiment it is 25% by weight or more and 65% by weight or less. By setting it within the above range, good ionic conductivity can be achieved.

[0017] The amount of NaTaCl6 crystals may be 0% by weight or more, 5% by weight or more, 10% by weight or more, 15% by weight or more, 25% by weight or more, 30% by weight or more, 35% by weight or more, or 45% by weight or more, and may also be 65% by weight or less, 55% by weight or less, 45% by weight or less, 35% by weight or less, 25% by weight or less, 15% by weight or less, 10% by weight or less, 8% by weight or less, 3% by weight or less, or 1% by weight or less, preferably 35% by weight or less, and in one embodiment, 0% by weight or more and 35% by weight or less. By setting it within the above range, good ionic conductivity can be achieved.

[0018] The amount of amorphous material and the amount of crystal chambers described above can be calculated using the RIR (Reference Intensity Ratio) method by subjecting the ion-conducting composite to X-ray diffraction together with a reference sample and determining the intensity ratio. Specifically, this can be determined by the method described in the examples.

[0019] [Method for producing electrolytes] The method for producing the electrolyte described herein involves mixing raw materials in a predetermined ratio and reacting them.

[0020] Examples of raw materials include combinations of tantalum chloride (especially TaCl5) and NaCl in a predetermined ratio.

[0021] The method for producing the electrolyte according to this disclosure preferably includes a mechanochemical treatment. The mechanochemical treatment may be a wet method or a dry method.

[0022] Mechanochemical processing is a method of grinding and mixing raw materials while applying mechanical energy to induce a reaction. In this method, the raw materials are subjected to mechanical impact and friction, causing them to come into intense contact with each other, which promotes the reaction and changes in the crystalline phase.

[0023] The equipment used for mechanochemical processing can be any device that can mix while applying mechanical energy, such as ball mills, bead mills, jet mills, vibratory mills, disc mills, turbo mills, and mechanofusions. Ball mills, especially planetary ball mills, can efficiently generate high impact energy because the pot rotates on its own axis while the base rotates in the opposite direction to the pot's axis. Processing conditions can be set appropriately according to the equipment used, the desired particle size, and the rate of reaction. For example, when using a planetary ball mill, conditions such as a ball diameter of 2 mm to 10 mm, a rotation speed of 50 to 1000 revolutions per minute, a processing time of 0.1 to 100 hours, and 1 to 100 kWh / kg of raw material can be used. From the viewpoint of increasing the rate of reaction, the rotation speed may be 100 revolutions per minute or more, for example, 300 revolutions per minute or more, and the processing time may be 1 hour or more, for example, 10 hours or more.

[0024] The temperature during the mechanochemical treatment may be 200°C or lower, 150°C or lower, 100°C or lower, 75°C or lower, or 50°C or lower, preferably 100°C or lower, and particularly 50°C or lower. Within this range, the electrolyte of this disclosure having a predetermined amorphous phase / crystalline ratio is easily formed.

[0025] The particle size of the electrolyte after mechanochemical treatment may be 50 μm or less, 30 μm or less, 20 μm or less, 10 μm or less, or 1 μm or less.

[0026] In each stage of the manufacturing process, it is preferable to use an inert gas atmosphere such as a nitrogen gas atmosphere or an argon gas atmosphere in order to suppress side reactions of the materials.

[0027] <Battery components / batteries> [Type of battery, etc.] The electrolyte in this disclosure can be suitably used as a solid electrolyte in each component of a battery, particularly a sodium-ion battery (one or more of the positive electrode, negative electrode, and solid electrolyte layer, for example, one of them). The battery (sodium-ion battery) may be a battery using a liquid electrolyte or an all-solid-state battery, and is preferably an all-solid-state battery.

[0028] There is no particular limitation on the shape of the battery, and it may be cylindrical, rectangular, or the like.

[0029] [Positive Electrode] The positive electrode contains a positive electrode active material. The positive electrode may contain other components such as the electrolyte, conductive auxiliary material, binder, etc. of the present disclosure as needed.

[0030] Examples of the positive electrode active material include materials capable of occluding or releasing sodium ions during charge and discharge, such as sodium cobaltate (NaCoO2), sodium nickelate (NaNiO2), sodium manganate (NaMn2O4), sodium iron phosphate (NaFePO4), vanadium oxide-based materials, sulfur-based materials, etc. Specific examples include NaCoO2, NaCoN, NaMnO2, NaMn2O4, Na , ,

[0031] , y MnO2, NaNi 0.5 Mn 0.5 O2, NaCo 1 / 3 Ni 1 / 3 Mn 1 / 3 O2, NaNiO2, NaVO2, NaFeO2, NaCrO2, NaVPO4F, Na2FePO4F, Na3V2(PO4)3, Na2FeS2-Na3PS4, V2O5, MoO3, TiS2, FeS, InSb, CuSb, MnSb, NaSn, NaSi, NaAl, NaGe, NaSb, Na(Ni x Mn 1-x )O2(0 < x < 1), Na(Fe x Mn 1-x )O2(0 < x < 1), Na 1+x Mn 2-x-y M y O4 (M is one or more metal elements selected from Al, Mg, Co, Fe, Ni, and Zn, 0 < x + y < 2), etc.

[0031] The amount of positive electrode active material in the positive electrode may be 10% by weight or more, 20% by weight or more, 30% by weight or more, 40% by weight or more, 60% by weight or more, 80% by weight or more, 90% by weight or more, or 95% by weight or more, for example, 50% by weight or more, preferably 75% by weight or more, more preferably 85% by weight or more, and particularly 90% by weight or more, and may also be 100% by weight or less, 95% by weight or less, 90% by weight or less, 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, or 20% by weight or less.

[0032] Examples of electrolytes include the electrolytes described herein and known electrolytes (for example, the electrolytes in the electrolyte layer described later).

[0033] The amount of the electrolyte of this disclosure in the positive electrode may be 0.5% by weight or more, 1% by weight or more, 3% by weight or more, 5% by weight or more, 10% by weight or more, 20% by weight or more, 30% by weight or more, or 40% by weight or more, and may also be 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, or 3% by weight or less.

[0034] The amount of electrolytes other than the electrolyte of this disclosure in the positive electrode may be 0.5% by weight or more, 1% by weight or more, 3% by weight or more, 5% by weight or more, 10% by weight or more, 20% by weight or more, 30% by weight or more, or 40% by weight or more, and may also be 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, or 3% by weight or less.

[0035] Examples of conductive additives include carbon materials such as graphite, coke, carbon black, acicular carbon, carbon fibers, and carbon nanotubes.

[0036] The amount of conductive additive in the positive electrode may be 0.1% by weight or more, 0.3% by weight or more, 0.4% by weight or more, 0.5% by weight or more, 1% by weight or more, 3% by weight or more, 5% by weight or more, 10% by weight or more, or 20% by weight or more, and may also be 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, or 0.5% by weight or less, and in one embodiment, it is preferably 0.2% by weight or more and 10% by weight or less, and particularly 0.4% by weight or more and 2% by weight or less.

[0037] Examples of binders include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polyimide (PI), polyamide, polyamide-imide, polyacrylic, styrene-butadiene rubber (SBR), styrene-ethylene-butylene-styrene copolymer (SEBS), and carboxymethylcellulose (CMC).

[0038] The amount of binder in the positive electrode may be 0.1% by weight or more, 0.3% by weight or more, 0.4% by weight or more, 0.5% by weight or more, 1% by weight or more, 3% by weight or more, 5% by weight or more, 10% by weight or more, or 20% by weight or more, and may also be 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, or 0.5% by weight or less, and in one embodiment, it is preferably 0.2% by weight or more and 10% by weight or less, and particularly 0.4% by weight or more and 2% by weight or less.

[0039] The positive electrode containing the above-mentioned components is connected to a positive electrode current collector made of Al, Ni, stainless steel, carbon cloth, or the like. The positive electrode may also be formed by coating the surface of the current collector with a slurry of the above-mentioned components mixed with an inert solvent and drying it.

[0040] [Negative electrode] The negative electrode includes a negative electrode active material. The negative electrode may optionally include other components such as the electrolyte, conductive additive, and binder of this disclosure.

[0041] Examples of negative electrode active materials include materials capable of intercalating or releasing sodium ions during charging and discharging, such as metallic sodium, carbon-based materials (activated carbon, graphite, etc.), silicon, silicon oxide, Si-SiO-based materials, and sodium titanium oxide. Specific examples include Na, Na alloys, carbon-based negative electrode active materials (hard carbon, natural graphite, artificial graphite, etc.), and Sn-based negative electrode active materials (NaSn2, Na2Sn, Na2Sn5, Na 15 Sn 4、 SnO 2、 NaSnO, CaSnO3, BaSnO 3、 Sn4P3, SnP), sodium titanate (Na2Ti3O7, Na4Ti5O 12 Examples include Si, Si alloys, Si-based negative electrode active materials, cobalt oxide, iron sulfide, Sb, Na-Sb alloys, P, P alloys, etc.

[0042] The amount of negative electrode active material in the negative electrode may be 10% by weight or more, 20% by weight or more, 30% by weight or more, 40% by weight or more, 60% by weight or more, 80% by weight or more, 90% by weight or more, or 95% by weight or more, for example, 50% by weight or more, preferably 75% by weight or more, more preferably 85% by weight or more, and particularly 90% by weight or more, and may also be 100% by weight or less, 95% by weight or less, 90% by weight or less, 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, or 20% by weight or less.

[0043] Examples of electrolytes include the electrolytes described herein and known electrolytes (for example, the electrolytes in the electrolyte layer described later).

[0044] The amount of the electrolyte of this disclosure in the negative electrode may be 0.5% by weight or more, 1% by weight or more, 3% by weight or more, 5% by weight or more, 10% by weight or more, 20% by weight or more, 30% by weight or more, or 40% by weight or more, and may also be 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, or 3% by weight or less.

[0045] The amount of electrolytes other than the electrolyte of this disclosure in the negative electrode may be 0.5% by weight or more, 1% by weight or more, 3% by weight or more, 5% by weight or more, 10% by weight or more, 20% by weight or more, 30% by weight or more, or 40% by weight or more, and may also be 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, or 3% by weight or less.

[0046] Examples of conductive additives include carbon materials such as graphite, coke, carbon black, acicular carbon, carbon fibers, and carbon nanotubes.

[0047] The amount of conductive additive in the negative electrode may be 0.1% by weight or more, 0.3% by weight or more, 0.4% by weight or more, 0.5% by weight or more, 1% by weight or more, 3% by weight or more, 5% by weight or more, 10% by weight or more, or 20% by weight or more, and may also be 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, or 0.5% by weight or less, and in one embodiment, it is preferably 0.2% by weight or more and 10% by weight or less, and particularly 0.4% by weight or more and 2% by weight or less.

[0048] Examples of binders include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polyimide (PI), polyamide, polyamide-imide, polyacrylic, styrene-butadiene rubber (SBR), styrene-ethylene-butylene-styrene copolymer (SEBS), and carboxymethylcellulose (CMC).

[0049] The amount of binder at the negative electrode may be 0.1% by weight or more, 0.3% by weight or more, 0.4% by weight or more, 0.5% by weight or more, 1% by weight or more, 3% by weight or more, 5% by weight or more, 10% by weight or more, or 20% by weight or more, and may also be 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, or 0.5% by weight or less, and in one embodiment, it is preferably 0.2% by weight or more and 10% by weight or less, and particularly 0.4% by weight or more and 2% by weight or less.

[0050] The negative electrode containing the above-mentioned components is connected to a negative electrode current collector made of Al, Ni, Cu, stainless steel, carbon cloth, or the like. The negative electrode may also be formed by coating the surface of the current collector with a slurry of the above-mentioned components mixed with an inert solvent and drying it.

[0051] [Electrolyte layer] The electrolyte layer may contain the electrolyte of this disclosure. The electrolyte layer may also contain other components, such as a binder, as needed. In a battery, the electrolyte layer is arranged to connect the positive electrode and the negative electrode.

[0052] Electrolyte layers can be broadly classified into liquid electrolyte layers, which primarily use liquid electrolytes, and solid electrolyte layers, which primarily use solid electrolytes.

[0053] (liquid electrolyte layer) The liquid electrolyte layer preferably consists of a mixture of an electrolyte and a non-aqueous solvent that dissolves and disperses it.

[0054] Examples of electrolytes in a liquid electrolyte layer include NaClO4, NaPF6, NaBF4, NaTiF4, NaVF5, NaAsF, NaAsF6, NaSbF6, NaCF3SO3, NaB(C2O4)2, NaB(C6H5)4, and NaB 10 Cl 10 NaB 12 Cl 12Examples include Na2SO4, Na2S2O4, NaNO3, NaCl, NaBr, CH3SO3Na, CF3SO3Na, NaN(SO2CF3)2, NaN(SO2C2F5)2, NaC(SO2CF3)3, or NaN(SO3CF3)2.

[0055] Examples of non-aqueous solvents include carbonates, ethers, ketones, sulfolane compounds, lactones, nitriles, chlorinated hydrocarbons, amines, esters, amides, and phosphate ester compounds. Representative examples of these include 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, ethylene carbonate, vinylene carbonate, methyl formate, dimethyl sulfoxide, propylene carbonate, acetonitrile, γ-butyrolactone, dimethylformamide, dimethyl carbonate, diethyl carbonate, sulfolane, ethyl methyl carbonate, 1,4-dioxane, 4-methyl-2-pentanone, 1,3-dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, sulfolane, methylsulfolane, propionitrile, benzonitrile, butyronitrile, valeronitrile, 1,2-dichloroethane, trimethyl phosphate, triethyl phosphate, and the like.

[0056] The amount of the electrolyte of this disclosure in the liquid electrolyte layer may be 40% by weight or more, 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, 90% by weight or more, 95% by weight or more, or 97.5% by weight or more, preferably 80% by weight or more, more preferably 95% by weight or more. Alternatively, it may be 100% by weight or less, 95% by weight or less, 90% by weight or less, 85% by weight or less, 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, or 3% by weight or less, and in one embodiment, it is 80% by weight or more and 100% by weight or less, particularly 95% by weight or more and 100% by weight or less.

[0057] The amount of electrolytes other than the electrolyte of this disclosure in the liquid electrolyte layer may be 0.5% by weight or more, 1% by weight or more, 3% by weight or more, 5% by weight or more, 10% by weight or more, 20% by weight or more, 30% by weight or more, or 40% by weight or more, and may also be 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, or 3% by weight or less.

[0058] The amount of non-aqueous solvent in the liquid electrolyte layer may be 0.5% by weight or more, 1% by weight or more, 3% by weight or more, 5% by weight or more, 10% by weight or more, 20% by weight or more, 30% by weight or more, or 40% by weight or more, and may also be 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, or 3% by weight or less.

[0059] The liquid electrolyte layer may include a separator to prevent short circuits between the positive and negative electrodes. The separator can be made of materials such as polyethylene, polypropylene, or other polyolefin resins; fluororesins such as polyvinylidene fluoride; nylon; cellulose acetate; nitrocellulose; polysulfone; polyacrylonitrile; aromatic aramid; or inorganic glass. The material may be in the form of a porous membrane, nonwoven fabric, or woven fabric.

[0060] (solid electrolyte layer) Examples of the solid electrolyte constituting the solid electrolyte layer include, in addition to the electrolyte of the present disclosure, known sodium ion conductive materials, such as sulfide-based solid electrolytes, oxide-based solid electrolytes, etc. Specifically, for example, Na2S-P2S5, Na2S-P2S5-NaI, Na2S-P2S5-NaI-NaBr, Na2S-P2S5-Na2O, Na2S-P2S5-Na2O-NaI, Na2S-SiS2, Na2S-SiS2-SiO2, Na2S-SiS2-NaI, Na2S-SiS2-NaBr, Na2S-SiS2-NaCl, Na2S-SiS2-B2S3-NaI, Na2S-SiS2-P2S5-NaI, Na2S-B2S3, Na2S-B2S3-SiO2, Na2S-GeS2-Ga2S3, Na2S-P2S5-GeS2, Na2S-GeS2, NaI-Na2S-P2O5, NaI-Na3PO4-P2S5, Na2S-P2S5, Na 10 GeP2S 12 、Na 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 、Na7P3S 11 、Na3PS4、Na 3.25 P 0.75 S4、Na6PS5I、Na 2.88 Sb 0.88 W 0.12 S 4、 Na 6-y PS 5-x Z 1+y (Z = Cl or Br, 0 < x < 5, 0 < y < 6) and other sulfide-based solid electrolytes, Na2O-B2O3-P2O3, Na2O-SiO2, Na2O-P2O5, Na5La3Ta2O 12 、Na7La3Zr2O 12 、Na3Zr2Si2PO 12 、Na6BaLa2Ta2O 12 Na 3.6 Si 0.6 P 0.4 O4 or Na3BO3-Na2SO4-Na2CO3 and other oxide-based solid electrolytes can be mentioned.

[0061] The amount of the electrolyte of this disclosure in the solid electrolyte layer may be 40% by weight or more, 50% by weight or more, 60% by weight or more, 70% by weight or more, 80% by weight or more, 90% by weight or more, 95% by weight or more, or 97.5% by weight or more, preferably 80% by weight or more, more preferably 95% by weight or more. Alternatively, it may be 100% by weight or less, 95% by weight or less, 90% by weight or less, 85% by weight or less, 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, or 3% by weight or less, and in one embodiment, it is 80% by weight or more and 100% by weight or less, particularly 95% by weight or more and 100% by weight or less.

[0062] The amount of electrolytes other than the electrolyte of this disclosure in the solid electrolyte layer may be 0.5% by weight or more, 1% by weight or more, 3% by weight or more, 5% by weight or more, 10% by weight or more, 20% by weight or more, 30% by weight or more, or 40% by weight or more, and may also be 80% by weight or less, 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, or 3% by weight or less.

[0063] The electrolyte layer may contain other components besides the electrolyte, such as a binder. Examples of binders include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polyimide (PI), polyamide, polyamide-imide, polyacrylic, styrene-butadiene rubber (SBR), styrene-ethylene-butylene-styrene copolymer (SEBS), and carboxymethylcellulose (CMC).

[0064] The amount of binder in the solid electrolyte layer may be 0.1% by weight or more, 0.3% by weight or more, 0.4% by weight or more, 0.5% by weight or more, 1% by weight or more, 3% by weight or more, 5% by weight or more, 10% by weight or more, or 20% by weight or more, and may also be 30% by weight or less, 20% by weight or less, 10% by weight or less, 5% by weight or less, 3% by weight or less, 2% by weight or less, 1% by weight or less, or 0.5% by weight or less, and in one embodiment, it is preferably 0.2% by weight or more and 10% by weight or less, and particularly 0.4% by weight or more and 2% by weight or less.

[0065] The solid electrolyte layer can be obtained by pressing the solid electrolyte to a predetermined thickness. The pressing pressure may be between 50 and 2000 MPa.

[0066] [Battery manufacturing method] (liquid electrolyte battery) When manufacturing a battery using a liquid electrolyte, for example, a sodium-ion battery or secondary battery can be obtained by inserting a laminate of a positive electrode, a separator, and a negative electrode into a battery case and pouring a mixture of the electrolyte and a non-aqueous solvent into the battery case. The positive electrode, separator, and negative electrode may be laminated or in a wound shape.

[0067] (All-solid-state battery) In manufacturing an all-solid-state battery, a cell is obtained by stacking a positive electrode, a solid electrolyte layer, a negative electrode, and a current collector, and then pressing them together. The thickness of each layer can be independently, for example, 0.1 μm or more, 1 μm or more, 10 μm or more, 100 μm or more, or 1000 μm or more, and can be 50000 μm or less, 30000 μm or less, 10000 μm or less, 5000 μm or less, 1000 μm or less, 500 μm or less, 300 μm or less, or 100 μm or less. In one embodiment, the thickness is 1 μm or more and 1000 μm or less, particularly 1 μm or more and 100 μm or less. The obtained cell is fixed to a housing as needed.

[0068] Although embodiments have been described above, it should be understood that various modifications to the form and details are possible without departing from the spirit and scope of the claims. [Examples]

[0069] The present disclosure will be described in detail below with reference to examples, but the present disclosure is not limited to these examples.

[0070] <Example: Synthesis and evaluation of NaTaCl6·xNaCl> In the following, unless otherwise specified, experiments were conducted in a glove box under a dry argon atmosphere.

[0071] [Electrolyte synthesis] NaCl (manufactured by Kanto Chemical Co., Ltd., purity 99.995%) and TaCl5 (manufactured by Kojunsei Chemical Co., Ltd., purity 99.99%) were mixed in a predetermined molar ratio and subjected to mechanochemical treatment using a ball mill to obtain NaTaCl6·xNaCl. The mechanochemical conditions were as follows. Planetary ball milling apparatus: Fritsch, Pulverisette 7 ZrO2 pot: 45mL ZrO2 ball: 5mm diameter, 60g Sample amount: 0.6g Rotation speed: 510 rpm Time: 30h Composition: x=0~15 Figure 1 shows the images obtained by performing SEM-EDX on the acquired electrolytes.

[0072] [XRD measurement] XRD measurements were performed on the electrolytes obtained above. The measurement conditions were as follows: X-ray diffraction measurements were performed to identify the crystalline phase of the prepared sample. A Rigaku Smart Lab fully automated multi-purpose horizontal X-ray diffractometer was used for the measurements. Powdered samples were measured using an airtight sample stage. CuKα rays (λ = 1.54056 × 10⁻¹) were used as the irradiation beam. -10 Using m), measurements were taken with a tube voltage of 40kV, a tube current of 200mA, and a scanning angle of 2θ = 10 to 80 degrees for normal measurements and 2θ = 5 to 80 degrees for RIR method measurements. The sampling interval was 0.02 degrees, and the scanning speed was 10 degrees min for normal measurements.-1 For measurements used in RIR analysis, 1 deg.min -1 That's what I decided.

[0073] The results are shown in Figure 2. Peaks attributed to NaCl were observed for all compositions, and it was confirmed that as the amount added increased, the peak intensity derived from NaTaCl6 decreased, while the peak intensity derived from NaCl increased.

[0074] [Quantification of amorphous / crystalline materials by RIR method] XRD measurements were performed on a composition prepared by mixing the electrolyte obtained above with the reference sample (Al2O3) in a weight ratio of 1:1, under the same conditions as the XRD measurements described above. Based on the comparison of the X-ray diffraction intensity ratio with the reference sample in the obtained XRD pattern, the weight fraction (%) and volume fraction (%) of amorphous material, NaTaCl6 crystals, and NaCl crystals in the electrolyte were calculated. In calculating the volume fraction, the density of amorphous material and NaTaCl6 crystals was assumed to be the same, and the following values ​​were used. Amorphous and NaTaCl6 crystals: 3.29 g / cm³ -3 NaCl crystal: 2.17gcm -3 The results are shown in Figures 3-1 (volume fraction) and 3-2 (weight fraction). As x increased, the change in the amount of amorphous material was small, while the amount of NaTaCl6 crystals decreased and the amount of NaCl tended to increase.

[0075] [AC Impedance Measurement] The electrolytes obtained above were subjected to AC impedance measurements, and their activation energy and ionic conductivity were determined from the results. The measurement conditions were as follows: AC impedance measurements were performed to calculate the ionic conductivity of the prepared sample. The powdered sample was placed in a pelletizer and pressed uniaxially at room temperature under a pressure of 360 MPa for 5 minutes using a hydraulic press to produce pelletized powder bodies. Gold was sputtered onto both sides of the obtained pellets as a current collector using a Quick Coater (QUICK COATER SC-701 MkII ADVANCED). Then, aluminum lead tabs, nickel lead tabs, and a laminate sheet were layered and the three sides were bonded together by heating with a sealer. The pellets were placed in this laminate cell and vacuum-sealed in a glove box under a dry argon atmosphere. Measurements were performed while varying the temperature of the measurement system using an oil bath. An impedance analyzer (SI-1260) was used. The measurement conditions were frequency 10 7 -10 -1 The frequency was set to Hz and the applied voltage to 50mV.

[0076] The results are shown in Figures 4-1, 4-2, and 4-3. As shown in Figures 4-1 and 4-3, a tendency was observed for the activation energy to decrease and the ionic conductivity to increase as x increased from x=0 to x=8, and a tendency for the activation energy to increase and the ionic conductivity to decrease as x increased from x=8 to x=15. The maximum room temperature ionic conductivity was 1.1 × 10 at x=8. -3 Scm -1 This was confirmed. As shown in Figure 4-2, it was confirmed that good ionic conductivity is exhibited even over a wide temperature range. Furthermore, while the ionic conductivity is equivalent to that of x=0 when x=1 or x=15, having ionic conductivity equal to or better than x=0 is industrially advantageous because a higher proportion of inexpensive NaCl can be used as a raw material as x increases. Considering the amorphous / crystalline fraction results obtained by the RIR method described above, it is suggested that the presence of an interface between amorphous material and NaCl crystals may indicate the existence of a high-speed ion conduction pathway at that interface. [Brief explanation of the drawing]

[0077] [Figure 1] SEM-EDX image of NaTaCl6·xNaCl. [Figure 2] XRD pattern of NaTaCl6·xNaCl. [Figure 3-1] Amorphous / crystalline fraction (volume fraction) calculated by the RIR method of NaTaCl6·xNaCl. [Figure 3-2] Amorphous / crystalline fraction (weight fraction) calculated by the RIR method for NaTaCl6·xNaCl. [Figure 4-1] Ionic conductivity (25°C) and activation energy of NaTaCl6·xNaCl. [Figure 4-2] Temperature dependence of the ionic conductivity of NaTaCl6·xNaCl. [Figure 4-3] Composition dependence of the ionic conductivity of NaTaCl6·xNaCl.

Claims

1. formula: NaTaCl ６ ・xNaCl [In the equation, x is between 1 and 15 (inclusive).] An electrolyte represented by [a specific symbol / method].

2. The electrolyte according to claim 1, wherein x is 4 or more and 11 or less.

3. In the aforementioned electrolyte, The amount of amorphous material is 10% by volume or more. The amount of NaCl crystals is 10% by volume or more. NaTaCl ６ The electrolyte according to claim 1 or 2, wherein the amount of crystals is 60 volume percent or less.

4. In the aforementioned electrolyte, The amount of amorphous material is 30% by volume or more and 60% by volume or less. The amount of NaCl crystals is 30% by volume or more and 70% by volume or less. NaTaCl ６ The electrolyte according to claim 1 or 2, wherein the amount of crystals is 30 volume percent or less.

5. The electrolyte according to claim 1 or 2, which is a solid electrolyte for an all-solid-state sodium-ion battery.

6. A positive electrode comprising the electrolyte described in claim 1 or 2.

7. A negative electrode comprising the electrolyte described in claim 1 or 2.

8. An electrolyte layer comprising the electrolyte described in claim 1 or 2.

9. A battery comprising a battery component containing the electrolyte described in claim 1 or 2.

10. formula: NaTaCl ６ ・xNaCl [In the equation, x is between 1 and 15 (inclusive).] A method for producing an electrolyte, represented by the following: A manufacturing method comprising a mechanochemical process for mixing and reacting raw materials.

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